Compensated foundation - Revision history

Designing Buildings at 08:47, 11 October 2020

2020-10-11T08:47:59Z

← Older revision		Revision as of 08:47, 11 October 2020
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	* Winchester House.		* Winchester House.

−	[[Category:Construction_techniques]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]]

Editor at 17:44, 5 June 2020

2020-06-05T17:44:08Z

← Older revision		Revision as of 17:44, 5 June 2020
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	* Swimming pool construction.		* Swimming pool construction.
	* Underpinning.		* Underpinning.
		+	* Winchester House.

	[[Category:Construction_techniques]]		[[Category:Construction_techniques]]

Designing Buildings at 16:55, 26 February 2020

2020-02-26T16:55:51Z

← Older revision		Revision as of 16:55, 26 February 2020
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	= Compensated piled raft foundations =		= Compensated piled raft foundations =

−	Compensated piled raft foundations are typically used where the soil provides only modest bearing capacity, meaning that piles are necessary to carry some of the load. This can necessary, for example, in the case of soft clay, which may undergo settlement due to reclamation filling or dewatering processes, during which the soil may settle away from the raft base.	+	Compensated piled raft foundations are typically used where the soil provides only modest bearing capacity, meaning that piles are necessary to carry some of the load. This can be necessary, for example, in the case of soft clay, which may undergo settlement due to reclamation filling or dewatering processes, during which the soil may settle away from the raft base.

	= Related articles on Designing Buildings Wiki =		= Related articles on Designing Buildings Wiki =

Designing Buildings at 16:51, 26 February 2020

2020-02-26T16:51:19Z

← Older revision		Revision as of 16:51, 26 February 2020
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	= Compensated raft foundations =		= Compensated raft foundations =

−	Where soil is compressible, ~~the~~ a raft foundation may be formed as a compensated foundation. In this case, the raft slab is provided to a depth that the weight of the excavated soil is equal to the raft slab weight plus that of the structure to be supported. This can be appropriate when constructing buildings on soft clay or loose sand, as settlement can be significantly reduced.	+	Where soil is compressible, a raft foundation may be formed as a compensated foundation. In this case, the raft slab is provided to a depth that the weight of the excavated soil is equal to the raft slab weight plus that of the structure to be supported. This can be appropriate when constructing buildings on soft clay or loose sand, as settlement can be significantly reduced.

	= Compensated piled raft foundations =		= Compensated piled raft foundations =
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	Compensated piled raft foundations are typically used where the soil provides only modest bearing capacity, meaning that piles are necessary to carry some of the load. This can necessary, for example, in the case of soft clay, which may undergo settlement due to reclamation filling or dewatering processes, during which the soil may settle away from the raft base.		Compensated piled raft foundations are typically used where the soil provides only modest bearing capacity, meaning that piles are necessary to carry some of the load. This can necessary, for example, in the case of soft clay, which may undergo settlement due to reclamation filling or dewatering processes, during which the soil may settle away from the raft base.

−	~~= Find out more =~~	+	= Related articles on Designing Buildings Wiki =
−		+
−	=== Related articles on Designing Buildings Wiki ===	+

	* Basement excavation.		* Basement excavation.

Editor at 18:08, 23 January 2018

2018-01-23T18:08:02Z

← Older revision		Revision as of 18:08, 23 January 2018
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	* Raft foundation.		* Raft foundation.
	* Settlement.		* Settlement.
		+	* Stepped foundation.
	* Strip foundation.		* Strip foundation.
	* Swimming pool construction.		* Swimming pool construction.

Designing Buildings at 13:57, 13 March 2017

2017-03-13T13:57:42Z

← Older revision		Revision as of 13:57, 13 March 2017
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	= Compensated piled raft foundations =		= Compensated piled raft foundations =

−	Compensated piled raft foundations are ~~less commonly~~ used~~, as~~ the soil ~~may provide~~ only a modest bearing capacity ~~and stiffness for the raft~~, meaning that ~~the~~ piles ~~have~~ to carry ~~the majority~~ of the load. This can ~~be exacerbated~~, in the case of soft clay, ~~if it undergoes~~ settlement due to reclamation filling or dewatering processes, as the soil may settle away from the raft base.	+	Compensated piled raft foundations are typically used where the soil provides only modest bearing capacity, meaning that piles are necessary to carry some of the load. This can necessary, for example, in the case of soft clay, which may undergo settlement due to reclamation filling or dewatering processes, during which the soil may settle away from the raft base.
−		+
−	~~However, there have been successful uses of piled rafts, most notably in Mexico City where compensated rafts were used with friction piles.~~	+
−		+
−	The construction process should be determined according to the situation, for example, the presence of groundwater. Some shallow excavations can allow piles to be installed from ground level, before excavation. Where greater depths are required, piling is carried out when part of, or the whole, excavation has been achieved.	+

	= Find out more =		= Find out more =

Designing Buildings at 13:54, 13 March 2017

2017-03-13T13:54:56Z

← Older revision		Revision as of 13:54, 13 March 2017
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	= Introduction =		= Introduction =

−	~~Compensated foundations are a type of deep foundation~~, ~~which work on the principle that if the weight~~ of soil and ~~water excavated equals the weight of the building added, the soil is subjected to no additional stresses. They are also known as ‘floating foundations’ due~~ to ~~the structure acting like a ship’s hull~~.	+	Foundations provide support for structures, transferring their load to layers of soil or rock that have sufficient bearing capacity and suitable settlement characteristics to support them.

−	~~In terms~~ of ~~stress~~, the relief of stress due to the excavation is approximately balanced by the applied stress of the foundation, resulting in a ~~very small~~ net stress. As a result there may be little consolidation settlement experienced.	+	Very broadly, foundations can be categorised as shallow or deep:
		+
		+	* Shallow foundations are typically used where the loads imposed by a structure are low relative to the bearing capacity of the surface soils.
		+	* Deep foundations are necessary where the bearing capacity of the surface soils is not sufficient to support the loads imposed by a structure and so those loads need to be transferred to deeper layers with higher bearing capacity.
		+
		+	Compensated foundations are a type of deep foundation, which work on the principle that if the weight of material excavated equals the weight of the building added, the soil is subjected to no additional stresses. They are also known as ‘floating foundations’ as the structure acts in a similar way to a ship’s hull.
		+
		+	The relief of stress due to the excavation is approximately balanced by the applied stress of the foundation, resulting in a negligible net stress. As a result there may be little consolidation settlement experienced.

	Compensated foundations normally comprise a deep basement and/or are used to support tall buildings or swimming pools, where a very large amount of material is excavated.		Compensated foundations normally comprise a deep basement and/or are used to support tall buildings or swimming pools, where a very large amount of material is excavated.

−	In addition to the control or elimination of settlement in the soil, other advantages ~~of compensated foundations are as follows~~:	+	In addition to the control or elimination of settlement in the soil, other advantages include:

−	* ~~Simple~~ construction process with minimal impact on adjacent structures.	+	* A simple construction process with minimal impact on adjacent structures.
−	* ~~Can~~ be integrated with other ~~works~~ in more complex ~~situation~~, such as piling.	+	* They can be integrated with other foundations in more complex situations, such as piling.
−	* ~~Provides~~ protection from rising damp, thermal insulation, drainage, and so on.	+	* They can contribute to protection from rising damp, thermal insulation, drainage, and so on.

	= Compensated raft foundations =		= Compensated raft foundations =

−	Where soil is compressible, ~~it can be~~ the ~~case that the total~~ raft foundation ~~is made~~ a compensated foundation. ~~This means that~~ the ~~raft slab involves excavation of the soil before construction of the foundation and the superstructure. The~~ raft slab is provided to a depth that the weight of the excavated soil is equal to the raft slab weight plus that of the structure to be supported.	+	Where soil is compressible, the a raft foundation may be formed as a compensated foundation. In this case, the raft slab is provided to a depth that the weight of the excavated soil is equal to the raft slab weight plus that of the structure to be supported. This can be appropriate when constructing buildings on soft clay or loose sand, as settlement can be significantly reduced.
−		+
−	This can be ~~very beneficial~~ when constructing buildings on soft clay or loose sand, as ~~the settlements that would occur if the foundation was located at or near the ground surface~~ can be significantly ~~lowered~~.	+

	= Compensated piled raft foundations =		= Compensated piled raft foundations =

Editor: Created page with "= Introduction = Compensated foundations are a type of deep foundation, which work on the principle that if the weight of soil and water excavated equals the weight of the build..."

2017-03-10T12:26:26Z

Created page with "= Introduction = Compensated foundations are a type of deep foundation, which work on the principle that if the weight of soil and water excavated equals the weight of the build..."

New page

= Introduction =

Compensated foundations are a type of deep foundation, which work on the principle that if the weight of soil and water excavated equals the weight of the building added, the soil is subjected to no additional stresses. They are also known as ‘floating foundations’ due to the structure acting like a ship’s hull.

In terms of stress, the relief of stress due to the excavation is approximately balanced by the applied stress of the foundation, resulting in a very small net stress. As a result there may be little consolidation settlement experienced.

Compensated foundations normally comprise a deep basement and/or are used to support tall buildings or swimming pools, where a very large amount of material is excavated.

In addition to the control or elimination of settlement in the soil, other advantages of compensated foundations are as follows:

* Simple construction process with minimal impact on adjacent structures.
* Can be integrated with other works in more complex situation, such as piling.
* Provides protection from rising damp, thermal insulation, drainage, and so on.

= Compensated raft foundations =

Where soil is compressible, it can be the case that the total raft foundation is made a compensated foundation. This means that the raft slab involves excavation of the soil before construction of the foundation and the superstructure. The raft slab is provided to a depth that the weight of the excavated soil is equal to the raft slab weight plus that of the structure to be supported.

This can be very beneficial when constructing buildings on soft clay or loose sand, as the settlements that would occur if the foundation was located at or near the ground surface can be significantly lowered.

= Compensated piled raft foundations =

Compensated piled raft foundations are less commonly used, as the soil may provide only a modest bearing capacity and stiffness for the raft, meaning that the piles have to carry the majority of the load. This can be exacerbated, in the case of soft clay, if it undergoes settlement due to reclamation filling or dewatering processes, as the soil may settle away from the raft base.

However, there have been successful uses of piled rafts, most notably in Mexico City where compensated rafts were used with friction piles.

The construction process should be determined according to the situation, for example, the presence of groundwater. Some shallow excavations can allow piles to be installed from ground level, before excavation. Where greater depths are required, piling is carried out when part of, or the whole, excavation has been achieved.

= Find out more =

=== Related articles on Designing Buildings Wiki ===

* Basement excavation.
* Footings.
* Foundations.
* Ground anchor.
* Pad foundation.
* Pile foundations.
* Raft foundation.
* Settlement.
* Strip foundation.
* Swimming pool construction.
* Underpinning.

[[Category:Construction_techniques]]